OpenAgTechnology · The technology side
Hardware &
Software.
The appropriate use of technology.
The big picture
Growing has always been two things: paying attention, and deciding what to do.
Technology doesn't change that. It lets you pay attention at a scale no person can reach alone — every greenhouse, every hour, even at 2 a.m. — and it remembers everything, so your decisions get better every season. Three moves, in order:
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01
Collect it
The senses
Measure what's actually happening — temperature, humidity, moisture, power — with something that never sleeps and never forgets to write it down. A sensor on an ESP32, a probe through Home Assistant, a meter pushing to the cloud: all just different ways to turn a real condition into a number you can trust.
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02
Have it
Data is king
Every reading stamped with when and where, kept clean, kept yours. That record is your operation's memory. It outlives the sensor that took it, the app that showed it, and the vendor that sold it. Organized, trustworthy data is the asset — everything else is replaceable.
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03
Use it
The payoff
See it on a dashboard. Get an alert before a failed heater becomes a lost crop. And as the record grows, let AI find patterns no person has time to see — things you can't do today. The catch is simple: AI can't tell you a thing about a crop you never measured.
Sensors, radios, Home Assistant, the cloud — those are the how, and there are many. Collect, have, use is the what. Get the what right and the how is just a choice that fits your operation. The Monitoring stack is the walk-up path through all of it.
Those numbers above are from a real farm in Middle Tennessee. They update every thirty seconds. The sensors are inexpensive and becoming commodity priced. The computer receiving them is smaller than a paperback book and once had another job in life. The software is free. The grower owns all of it. This is what appropriate technology looks like.
Farming is both an art and a science. Experience has no substitute. The use of technology in any industry should be to support the productivity and efficiency of the operation. The most basic and simple use of appropriate technology can have a giant-ass impact on productivity. The timely awareness of a temperature being out of range can change the outcome of the day. Not having to walk to the last greenhouse every hour to check temperature is efficiency. Simple example, simple technology. Appropriate for the need. Appropriate for the budget. Big and meaningful result.
The appropriate use of technology in agriculture is the message here. This applies to the smallest farms and to the largest, most sophisticated vertical farms. Budgets differ — the need is the same. You have to be aware of what is available to design a solution. You have to understand the basics to put together the pieces that build it. Components are inexpensive and readily available. Some knowhow and a little experience go a long way. If you understand it, build it, and own it, you can repair and maintain it. That is independence.
OpenAgTechnology is a collective of growers with a technical side and growers with a technical need. We share what we know about putting agricultural technology together — the sensors, the radios, the power, the software, the automations, and the hard-earned lessons about what works in a real field or greenhouse and what only works on a bench.
The library is open to read, use, and share. If you want to be part of the collective — to contribute, to get updates, to share what you've figured out — sign up. Your choice. Same as using technology is a choice.
We're not running a funnel. A grower who reads this site, goes home, builds a working monitoring system, and never talks to anyone here is exactly the kind of grower this site was built for. That's the point. Growers teach growers. Farmers teach farmers. If you need a bigger, more complex system, some collective members offer paid independent consulting and design services to help you learn and build what you need.
Welcome to the Future. Welcome to Open Agriculture Technology.
The name is a nod to what the site is about. Open as in open source, open data, open access, open door, open technology. Agriculture because that's the context — growing food, growing ornamentals, or growing weed (legally). Technology because it supports productivity, efficiency, compliance, and awareness — and because it lets a grower know about a problem in time to fix it. A tomato farmer in Tennessee, a vertical-farm engineer in Singapore, a cooperative grower in Kenya, a mushroom grower in France, a cannabis grower in Colorado, a ninth-grade agriculture student in Iowa — if you're trying to understand how modern agricultural technology actually works, this site is for you.
The Fundamentals
Start with the basics.
Eight lessons that teach the whole field from first principles. New to this? Read them in order. Coming back? Skim the intro and click the one you need.
The frame
Appropriate use of technology in the appropriate place.
That phrase carries more weight than it seems to at first. Most conversations about agricultural technology treat technology as a grade — the more advanced, the better. Appropriate technology rejects that frame. A technology isn't good or bad on its own. It's appropriate or inappropriate to a specific place, a specific problem, a specific operation, a specific grower.
A fifty-thousand-dollar commercial control system is appropriate technology in a five-hundred-thousand-square-foot operation where downtime costs thousands of dollars an hour. The same system dropped into a grower with two high tunnels is inappropriate — not because it's bad technology, but because it doesn't fit. A five-hundred-dollar system is just as important to a mushroom grower if it prevents a complete crop loss. A twenty-five-dollar sensor taped to a post with wire is appropriate technology in a backyard greenhouse. The same sensor in a pharmaceutical cannabis facility is inappropriate — not because it's bad, but because it doesn't fit.
Fit is the word.
When technology fits, it earns its place. When it doesn't, it becomes a drain — of money, of attention, of trust. Fit is easy to lose in the buying: a grower reaches for whatever's in front of them, and sometimes it works and sometimes it doesn't. Knowing what fits — before you buy or build — is the difference.
What Schumacher didn't have in 1973 was open-source software, commodity hardware made by the billion, cheap radios, cheap computers, and an internet to share knowledge on. He had the philosophy. He didn't have the platform. Fifty years later, the platform exists. The pieces are sitting on warehouse shelves and in software repositories, waiting for someone to put them together and share how it's done.
That's what this section is for. Putting the pieces together. Showing how it's done. Sharing knowhow.
Why this section exists
Growers can build. They often don't know how to architect a system.
A grower with a specific problem can find no shortage of products — names, prices from two hundred dollars to twenty thousand. What's harder to find is the know-how to tell which one fits the operation, and how to make the pieces work together.
Overheard at a farm show
I lost a crop last January when the heater failed overnight and nobody knew until morning.
Composite, from many growers, many farm shows
What the grower actually needs is different. The grower needs to understand the shape of the problem. A heater failed. Nobody knew. That's not one problem — it's three:
- The heater failed. A hardware question.
- Nobody knew. A monitoring and alert question.
- Nobody knew in time to act. A response question.
Solving one of the three without the other two leaves the grower exposed. A sensor that detects the cold but does not alert anyone does not help. An alert that fires at 3 AM with no one listening does not help. A call tree that works perfectly but depends on a sensor that failed six months ago does not help.
Architecting a system means thinking about all three. It means choosing components that work together. It means planning for failure modes. It means knowing which sensor to put where, which radio to use, how to keep the device powered, where the data goes, who gets notified, what gets automated, and what stays in human hands. None of that is in a product catalog. All of it is learnable. Almost none of it is written down in one place.
That's the gap this section addresses: the know-how to put together a system that fits the operation — whether a grower builds it from parts, buys it off the shelf, or has someone set it up.
The collective is how the knowledge grows.
One person knows a lot about one kind of agriculture. A vegetable grower in Georgia knows things a mushroom grower in a container doesn't. A hydroponic lettuce operation knows things an orchard doesn't. A grower in a desert climate has learned failure modes a grower in a humid climate has never seen. A researcher has access to data nobody in production has time to gather. An extension agent has seen patterns across hundreds of operations. A maker who builds their own sensors knows things an engineer designing commercial products doesn't.
Put them in a room and they'd teach each other for a month. The site is that room.
If you're a grower who's figured something out, we'd welcome the contribution. If you're a researcher with data that belongs in public, we'd welcome it. If you're an extension agent with a case study that would teach others, we'd welcome it. This site is what a growing network of people decide to put into it.
Where to start
You don't have to learn it all at once.
This stuff crosses a lot of worlds — growing, power, sensors, networks, software, automation, data. Nobody starts knowing all of it. Start where your problem or your curiosity is strongest. The rest connects as you go.
Eight lessons, first principles. Read them in order and the whole field stops being a fog.
I want to monitor and automate The Hort Assistant approachHow to turn Home Assistant and open tools into a real monitoring and control system for growing.
I build and fix things Browse the catalogSensors, controls, and components — what each is for, and where it does and doesn't fit.
I have a specific device in mind Open the device libraryPractical setup pages for the specific sensors and devices growers actually reach for.
Just explain the words Open the glossaryVPD, DLI, EC, PAR, MQTT, LoRa — plain-language first, technical second.
Status
What you'll find here right now.
The eight fundamentals lessons
Each one a substantive piece of writing that teaches its topic from first principles. More depth follows — calculators, reference tables, worked examples.
~90k words total · 266 FAQThe catalog
Specimen entries for the sensors, controls, and components the collective recommends. Where each fits — and where it does not.
SensorPush HT1 published · more on the wayThe Hort Assistant approach
How to configure Home Assistant for agricultural monitoring and control. What hardware works, what automations matter, what dashboards work.
Draft 1 · 18 FAQ · configurations library comingThe glossary
A growing reference of agricultural technology terms. Plain-language definition first, technical definition second. VPD, DLI, EC, PAR, PPFD, MQTT, LoRa.
30 terms seeded · expandingAbout
Who's in the collective, the history, and how to get in touch.
The live data widget
A working sample is on this page today. The production version — full sensor coverage, embeddable elsewhere — is coming next.
Guides, crop profiles, SOPs, case studies
Added as they're written.
Questions growers actually search.
Straight answers to the things people type into a search box — the methods, the hardware, and the words. Useful whether you found us or an answer engine quoted us.
What is Controlled Environment Agriculture (CEA)?
Controlled Environment Agriculture is growing crops in a space where conditions like temperature, humidity, light, airflow, and irrigation can be measured and managed. Greenhouses, high tunnels, indoor and vertical farms, hydroponic and aquaponic systems, mushroom rooms, and grow rooms are all forms of CEA. The point is consistency: the more of the environment you can see and steer, the less the crop is left to chance.
What is appropriate technology in farming?
Appropriate technology is technology that fits the operation — its scale, budget, skills, and the failure modes it can tolerate. A twenty-five-dollar sensor on a backyard greenhouse and a fifty-thousand-dollar control system in a commercial range can both be appropriate; each is wrong in the other's place. The test is fit, not sophistication. A tool earns its place when it solves a real problem without creating new ones.
How can I monitor my greenhouse temperature remotely?
Put a temperature sensor in the greenhouse, connect it to a small computer or a Wi-Fi device, and have it push readings to a dashboard or a phone alert. Options range from a single Wi-Fi sensor to an ESP32 or Raspberry Pi running open-source software like Home Assistant. What matters most is where the sensor sits, how reliable the power and connection are, and whether an alert actually reaches a person in time to act.
What is IoT in agriculture?
IoT — the Internet of Things — in agriculture means connected devices that measure or control real growing conditions: temperature, humidity, soil moisture, water level, light, pump and fan status, door position, power loss. Its value is simple: it lets a grower see what's happening when they aren't standing next to the crop, and act before a problem becomes a loss.
What sensors are useful for growers?
It depends on the crop and the room, but the common ones are temperature, humidity, soil or substrate moisture, light (PAR/PPFD), CO2, water level and flow, pH and EC for nutrient solutions, and current or power sensors that reveal when equipment fails. The most useful sensor is the one that answers a question you actually have, or warns you about a loss you actually fear.
How can technology help prevent crop loss?
By turning hidden conditions into early warnings. A temperature alert catches a heater failure before sunrise. Humidity and airflow data show mold pressure building before you can see it. Soil moisture readings stop both over- and under-watering. A current sensor reveals a stopped pump. Technology doesn't remove risk — it shortens the gap between when something goes wrong and when someone knows.
Can a small farm afford automation?
Yes. Automation doesn't have to mean robots or a commercial control system. A timer, a humidity-triggered fan, a temperature alert, or a dashboard that shows which system needs attention are all automation, and all cheap to start. Small operations often get the most from automation that catches failures early and removes repetitive checking.
What is VPD and why does it matter?
VPD, or vapor pressure deficit, is a single number that combines temperature and humidity to describe how strongly the air pulls moisture from a plant. It predicts transpiration, and with it the risk of stress, slow growth, or mold. Many growers steer by VPD instead of humidity alone because it tracks what the plant actually experiences, not just what the hygrometer reads.
Can Home Assistant be used for agriculture?
Yes. Home Assistant is open-source automation software that runs on a small local computer, and it works as well in a greenhouse as in a house. It can read sensors, show dashboards, send alerts, log history, and control fans, pumps, and lights — without depending on a vendor's cloud. Because it runs locally and the data stays with the grower, it fits the appropriate-technology approach well.
Why should a grower own their data?
Because the data describes their operation — its conditions, its crop history, its decisions — and that record grows more valuable over years. When it's locked inside a vendor's platform, a grower can lose access to their own trends the moment they stop paying. Owning and being able to export the data protects continuity, troubleshooting, and any future use with AI or research.
What is a smart greenhouse?
A smart greenhouse uses sensors, data, and some automation to monitor or manage growing conditions — temperature, humidity, light, irrigation, airflow, equipment status. It might send alerts, log trends, or run fans and pumps on conditions instead of guesswork. It doesn't have to be expensive or fully automated; even basic monitoring makes a greenhouse meaningfully smarter.
How much does greenhouse automation cost?
It ranges from under a hundred dollars to many thousands, depending on what you're controlling and how much reliability you need. A monitoring-and-alert setup built from commodity sensors and open-source software can be very cheap; a full commercial climate-control system is a large investment. The cheapest path that works is to define the one problem you're solving and build the simplest reliable thing that solves it.